ViscoMR is an integrated capillary viscometer and magnetic resonance imaging system to measure complex fluid rheology and visualize the velocity profile. ViscoMR is specifically designed to measure complex Non-Newtonian fluids like colloidal suspensions, fiber suspension and materials that exhibit yield stress and/or wall slip.
ViscoMR
ViscoMR integrates a syringe pump, pressure differential and magnetic resonance imaging system to visualize the velocity profile of complex fluids under stress. The ViscoMR is specifically designed to measure fluids which are difficult to measure due to dispersed solids and under process monitoring conditions. Additional magnetic resonance measurements (T1, T2, diffusion) can also be integrated into the measurement sequence.
Applications
- Food
- Personal care products
- Petroleum drilling mud
- Process monitoring
Additional Measurements
- Fluid composition
- Emulsion characterization
- Degree of mixing
- Percent Solids
Software
The ViscoMR integrates the classical pressure drop viscosity measurement with advanced MRI techniques to characterize complex fluid rheology and composition in a single compact instrument. The ViscoMR can be configured for the research laboratory and can also be easily adapted to the production area for on-line measurements. Typical measurement times can range from seconds to minutes depending upon the fluid properties.
The screen shot to the right shows the flow profile and calculation of the shear viscosity.
Conceptual Approach
A rheogram is generated from the pressure drop per unit length and velocity profile. The shear stress(τ) as a function of radial position is calculated from t(r)=(ΔP/2L)*r, where ΔP is the pressure drop, L is the length of pipe and r is the radial position. The shear rate is obtained direction from the derivative of the velocity profile as a function of radial position. Combining the two and eliminating the radial variable yields a shear stress shear rate curve or rheogram.
Standard Components
- Pump A syringe pump with 200 lbs. of linear force is controlled in the software to recharge and dispense fluid into the flow-loop.
- Flow loop Two pressure transducers and thermocouples are located up to 2 feet apart to measure the shear rate by using tubing from 1-8 mm id and varying the fluid velocity.
- Flow Imaging An advanced compact MRI system is used to measure the flow velocity. Additional measurements such as T1, T2 and diffusion can also be integrated into the measurement sequence
- MATLAB Environment All components are integrated into a MATLAB environment using our proprietary control software by McCarthy Engineering.
- Customizable Any number or components can be modified to accommodate the types of fluids of interest including high pressure syringe pumps, heated flow loops and sanitary fittings in the flow loop. The 80/20 gantry shelves and supports are fully adjustable and customizable.
- Air/Solvent/Vacuum Purge An integrated purge circuit allows for fast cleaning by compressed air, solvent, and vacuum. Vacuum pump is optional accessory.
References
- RL Powell, JE Maneval, JD Seymour, KL McCarthy, MJ McCarthy, J. Rheol. 38 1465 (1994)
- JE Maneval, KL McCarthy, MJ McCarthy, RL Powell, US Patent No 5532593 July 2 1993
- KL McCarthy, MJ McCarthy J. Food Sci 74 291 (2009)
- DM Lavenson, EJ Tozzi, MJ McCarthy, RL Powell Biotech & Bioeng. 2011
Specifications
- Shear rate range 0.1 to 1000 sec-1
- Measurement time less than 1 minute
- Standard pump 200 lbs linear force
- Standard tubing range 3 – 9 mm ID
- Stainless steel and non-magnetic construction
- Dimensions 24 x 24 x 60 inches (w x d x h)
- Weight 320 lbs